During the Enterprise's visit to the Shore Leave Planet, later that year, M'Ress was key in coordinating between Captain Kirk's landing party and the duty officer, Lieutenant CommanderScott. Among the messages she coordinated was a notice to the crew that all shore leaves were canceled until further notice, when it was determined that the planet's master computer had malfunctioned. During the attempted recovery of Uhura, who had been taken hostage, M'Ress arranged for the transport of a phaser bore. As the rescue attempt continued, M'Ress coordinated between the shuttlebay and Scott, relaying notice of the emergency rescue party's attempted shuttlecraft launch. When it was finally realized that the planet was somehow responsible for the ship's malfunctions, M'Ress became concerned about the change in the planet's behavior – from providing fun and amusement to hostility. When Scott tried to maneuver the ship from orbit, he requested a printout of the guidance computer's last orders. In reviewing the orders, she noted that something was very strange, and that the only reason why the new orders were not being carried out was because Lieutenant Arex had had all the engine controls manually locked. As the Enterprise crew continued their attempt to rescue the landing party, M'Ress reported that communications remained jammed. Once the situation on the surface was resolved, and communications were restored, M'Ress passed along word from Kirk that shore leave was to commence immediately. (TAS: "Once Upon a Planet")

She was again on duty on the bridge when Harry Mudd was taken aboard the Enterprise from Motherlode. She monitored ship-to-shore communications with the rescue party after Mudd had taken Christine Chapel hostage. When Spock beamed down to the surface of the planet to help Kirk find Mudd and Chapel, M'Ress also manned the main science station, for Spock, to keep track of the whereabouts of Spock and Kirk. (TAS: "Mudd's Passion")

During the Enterprise's visit to Lactra VII, M'Ress was stationed on the bridge when a Lactran youth, who had been inadvertently beamed on board the ship, came onto the bridge. M'Ress was initially startled by the creature's sudden appearance. She then inquired what she wanted everyone to do after the Lactran had picked Scott up. She and the rest of the crew left the bridge while Scott attempted to communicate with the creature. (TAS: "The Eye of the Beholder")

M'Ress continued duty as the relief communications officer in 2270, where she was stationed when Uhura was temporarily in command of the bridge during the Enterprise's mission to Delta Theta III. (TAS: "Bem")

M'Ress was again on the bridge later that year, when the Enterprise's computer fell under the influence of an energy field. As the crew of the ship fell victim to numerous practical jokes, M'Ress noticed fog emerging from the turbolift door. When she pointed out the anomaly, Kirk – who suspected her observation was another practical joke – told her, "Really, M'Ress, you're going to have to be a little more clever than that." M'Ress later reported McCoy, Sulu, and Uhura were still in the recreation room and not responding to the captain's call to stations. (TAS: "The Practical Joker")

Shortly after this, M'Ress had a brief romantic interest in Scott, while the ship was under the influence of Harry Mudd's love potion which had inadvertently spread through the ship's ventilation system. M'Ress' interest in Scott came in response to a joke he had made, to which she replied, "You're funny, and very attractive for a Human." Once the effects of the potion wore off, and Scott began to complain of a "hangover to shame all previous hangovers," M'Ress snarled, "Not so loud, you fool." In response, Scott snapped back, stating, "Yeah, well, all of a sudden, I don't like you much, either." (TAS: "Mudd's Passion")

M'Ress and Arex share lunch

In 2270, M'Ress shared lunch in the mess hall with Arex, who invited Scott to join them, but Scott declined because he was just going to grab a sandwich and get back to work. At the time, however, the ship's computer was under the influence of an energy field, which caused the food synthesizer to go haywire. Observing the resulting effect, a mountain of food piling up at Scott's feet, M'Ress began to laugh, apologetically, before Scott accused the two of causing the practical joke. When Arex defended himself and M'Ress, Scott told them to tell that to the captain, because he was going to put the two on report for the incident. (TAS: "The Practical Joker")

In the final draft script of "Mudd's Passion", M'Ress is described as "a felinoid female, delicate, sleek, reminding one of an Earth Siamese or Abyssinian cat." The same script goes on to say, "Her fur is a soft cream color; her voice has a distinctive purr in it."

According to M'Ress' Lincoln Enterprisesbiography, she graduated from Starfleet Academy "three years ago", specializing in communications and computer translator systems. She quickly rose in rank to lieutenant in a mere two years after graduation. Prior to her assignment on board the Enterprise, she had served aboard a scout and the USS Hood.

She is briefly referenced in The Face of the Unknown as being Uhura's trainee, indicating that her assignment to the Enterprise predated Arex's, as his transfer was imminent but hadn't happened yet by the end of the novel.